This is a great intercom circuit that can be used in
many ways. It uses 22V to operate and maybe it will work at a lower
voltage (you can try it). For input/output it uses a loundspeaker
(20-45 Ohm) on each side.


Click to enlarge

Intercommunication #2

Componets Layout

Intercommunication #3


Parts List

R1: 2,2 M

C6: 200uF/40V

R2: 10 Ohm

IC1: PA234

R3,R6: 100K

LS1,2: 20-45 Ohm

R4: 22K

T1: 2N3391 (BC383)

R5: 1M

P1: 5K

C1: 0,2uF


C2: 0,02uF

C3: 0,001uF

C4: 0,05uF

C5: 100uF/40V

*Intercommunication #4

See here how the SW should be. See also the large
theoritical image.

Sorry, comments are closed!